Sensitivity of Effluent Variables in Activated Sludge Process

2017 ◽  
Vol 13 (2) ◽  
Author(s):  
B Vivekanandan ◽  
K Jeyannathann ◽  
A. Seshagiri Rao

Abstract The quality of a treated effluent changes when there is a sudden variation in the influent flow to the wastewater treatment plant during dry, rain, and storm weather conditions. In this study, various influent flow conditions in an activated sludge process are considered that affect the sensitivity of effluent variables such as chemical oxygen demand (COD), biological oxygen demand (BOD), nitrate nitrogen (SNO), ammonical nitrogen (SNH), and total nitrogen (TN) with respect to varying internal recycle flow rate (Qa), sludge recycle flow rate (Qr), sludge wastage flow rate (Qw) and oxygen transfer rate co-efficient of aerobic tanks (KLa(3,4,5)). The analysis has been carried out based on benchmark simulation model no.1 (BSM 1) plant layout which comprises of two models namely activated sludge model no.1 (ASM 1) and simple one dimensional (Simple 1-D) Takacs model. Based on the present analysis, it is observed that the changes in influent flow rate have larger impact on the effluent variables. This variation can be subdued by introducing additional tanks to smoothen the perturbations or using internal recycle rate from the fifth tank in order to maintain the flow around the optimal influent flow rate. The sludge wastage rate has a greater impact on all effluent variables except nitrogenous variables during maximum flow conditions.

2020 ◽  
Vol 12 (19) ◽  
pp. 8182
Author(s):  
Nuhu Dalhat Mu’azu ◽  
Omar Alagha ◽  
Ismail Anil

Mathematical modeling has become an indispensable tool for sustainable wastewater management, especially for the simulation of complex biochemical processes involved in the activated sludge process (ASP), which requires a substantial amount of data related to wastewater and sludge characteristics as well as process kinetics and stoichiometry. In this study, a systematic approach for calibration of the activated sludge model one (ASM1) model for a real municipal wastewater ASP was undertaken in GPS-X. The developed model was successfully validated while meeting the assumption of the model’s constant stoichiometry and kinetic coefficients for any plant influent compositions. The influences of vital ASP parameters on the treatment plant performance and capacity analysis for meeting local discharge limits were also investigated. Lower influent chemical oxygen demand in mgO2/L (COD) could inhibit effective nitrification and denitrification, while beyond 250 mgO2/L, there is a tendency for effluent quality to breach the regulatory limit. The plant performance can be satisfactory for handling even higher influent volumes up to 60,000 m3/d and organic loading when Total Suspended Solids/Volatile Suspended Solids (VSS/TSS) and particulate COD (XCOD)/VSS are maintained above 0.7 and 1, respectively. The wasted activated sludge (WAS) has more impact on the effluent quality compared to recycle activated sludge (RAS) with significant performance improvement when the WAS was increased from 3000 to 9000 m3/d. Hydraulic retention time (HRT) > 6 h and solids retention time (SRT) < 7 days resulted in better plant performance with the SRT having greater impact compared with HRT. The plant performance could be sustained for a quite appreciable range of COD/5-day Biochemical Oxygen Demand (BOD5 in mgO2/L) ratio, Mixed Liquor Suspended Solid (MLSS) of up to 6000 mg/L, and when BOD5/total nitrogen (TN) and COD/TN are comparatively at higher values. This work demonstrated a systematic approach for estimation of the wastewater treatment plant (WWTP) ASP parameters and the high modeling capabilities of ASM1 in GPS-X when respirometry tests data are lacking.


1993 ◽  
Vol 28 (11-12) ◽  
pp. 355-367 ◽  
Author(s):  
Y. P. Tsai ◽  
C. F. Ouyang ◽  
M. Y. Wu ◽  
W. L. Chiang

The effluent total BOD (or COD) concentration of the activated sludge process (A.S.P.) usually increases with suspended solid concentration. How to reduce effluent S.S. concentration, therefore, is the key issue of treatment efficiency for A.S.P. The varied return sludge and influent flow rate are two major operational factors of those affecting effluent S.S. concentration. However, the wastewater flow rate and substrate concentration in municipal wastewater treatment plant, due to the differences of city scale and life style, are significantly time-varied every day. Based on the above, the purpose of this study is to control in timely fashion return sludge flow rate with the variation of influent flow rate to minimize effluent S.S. concentration and meanwhile decrease the effluent total BOD (or COD) concentration. The fuzzy control theory is utilized in this study to forecast and control effluent S.S. concentration and further predict the MLSS concentration in aeration tank. It reveals that the inferred control strategies not only enable one to decrease effluent S.S.


2006 ◽  
Vol 54 (3) ◽  
pp. 89-94 ◽  
Author(s):  
R. Cantusio Neto ◽  
J.U. Santos ◽  
R.M.B. Franco

Among many waterborne diseases the giardiasis and cryptosporidiosis are of particular public health interest, because Giardia cysts and Cryptosporidium oocysts can persist for long periods in the environment, and both pathogenic protozoa have been implicated as the cause of many outbreaks of gastroenteritis in the last 25 years. In order to evaluate the efficiency of cysts and oocysts' removal by the activated sludge process, and by UV reactor in inactivating cysts and oocysts in one wastewater treatment plant (WWTP) of Campinas, three sampling points were selected for study: (1) influent, (2) treated effluent without UV disinfection and (3) treated effluent with UV disinfection. Giardia spp. cysts prevailed with higher density in the three different sample types. Cryptosporidium spp. oocysts were observed in only two samples of influent and just one sample of treated sewage with UV disinfection. In the animal infectivity assay for Giardia spp, one mouse of the UV treated group revealed trophozoites in intestinal scrapings. The results of the present study indicate that treatment by activated sludge process delivered a reduction of 98.9% of cysts and 99.7% of oocysts and UV disinfection was not completely efficient regarding the inactivation of Giardia cysts in the case of the WWTP studied.


1976 ◽  
Vol 11 (1) ◽  
pp. 108-121
Author(s):  
N. Thérien ◽  
P. Harrington

Abstract The dynamic response of the activated sludge process in the wastewater treatment plant of the Centre Hospitalier Universitaire de Sherbrooke was analysed with respect to large disturbances in both the flow rate and the quality of wastewater entering the plant. A mass balance conducted for the organic substrate and biomass entering and leaving the process led to a model consisting of two separate differential equations in terms of BOD and VSS with a two-phase bio-kinetic relationship for the reaction term. Predictions of the model for BOD and VSS variations in time were compared to experimental observations at the plant. A model using mean daily values for VSS and expressed in terms of BOD for the stream flowing out the clarifier unit in response to flow rate and BOD cyclic fluctuations of the entering wastewater stream to the process was found apt at describing the time at which BOD peaks in the process effluent occurred as well as predicting the magnitude of these peaks. The dynamic behaviour of the activated sludge process has been simulated for periods of one to several days using this model. Its use in predicting appropriate control action in time in order to improve the treatment efficiency is also indicated.


2021 ◽  
Vol 11 (2) ◽  
pp. 15-24
Author(s):  
Nur Diana Wakimin ◽  
Juferi Idris ◽  
Lydia Dundun Francis ◽  
Maureen Neging ◽  
Siti Rafiqah Muskil ◽  
...  

Pollutants from sewage wastewater are major concerns due to their environmental effects. Thus, an effective sewage wastewater treatment plant is important to ensure discharged effluent is well treated before it can be released to rivers or water streams. This study aims to evaluate the performance of the Activated Sludge Hi-Kleen Treatment Plant (ASHTP) located at H Block (ASHTP at H Block) and L Block (ASHTP at L Block) in UiTM Sarawak Branch, Samarahan Campus, Sarawak, Malaysia. The evaluation was based on physicochemical and removal efficiency namely pH, temperature, turbidity, chemical oxygen demand (COD), and total suspended solids (TSS) from raw influent and treated effluent. The findings indicated that the overall performance of both ASHTP at H Block and L Block were satisfactory where treated effluent meets the standard discharge limits of Environmental Quality (Sewage) Regulations 2009 (Standard B). For ASHTP at H Block, the removal efficiencies of turbidity, COD, and TSS were found to be 86.00, 13.76, and 88.02% respectively, in which the pH, temperature, turbidity, COD, and TSS of the treated effluent were 7.30, 28.10°C, 10.40 NTU, 14.10 mg/L and 8.90 mg/L respectively. Meanwhile, for ASHTP at L Block, the removal efficiencies of turbidity, COD, and TSS were found to be 43.20, 41.90, and 51.61% respectively, in which the pH, temperature, turbidity, COD, and TSS in the treated effluent were 7.30, 27.90°C, 21.10 NTU, 58.10 mg/L and 18.00 mg/L respectively. Proper maintenance of sewage treatment plant is important to ensure its effectiveness as well as to prolong its lifespan.


2019 ◽  
pp. 349-356
Author(s):  
Kristo Kärmas ◽  
Toomas Tenno ◽  
Karin Hellat

The object of this work is to research the sulphide formation process in pressure pipesand how the sulphur rich wastewater influences treatment process in Kohtla-Jiirvewastewater treatment plant (WWTP),In this work the ISO 8192 standard test has been used to estimate the inhibition of oxygendemand of activated sludge microorganisms in different sulphide concentrations and pHvalues, Two wastewaters has been investigated - leachate from coke- and ash hills andwastewater from inflow ofKohtla-Jii.rve WWTP,The leachate from coke- and ash hills, rich of sulphates and sulphides, with high pHvalues from l O+ 12, did not cause significant inhibition of oxygen demand of activatedsludge microorganisms, After the leachate has been mixed with other sulphate andsulphide rich wastewaters with lower pH values, the mixed wastewater inhibits theoxygen demand of microorganisms in activated sludge process. One of the reasons is theincreased sulphide concentration but the essential factor is also decreasing of pH.


2007 ◽  
Vol 13 (4) ◽  
pp. 211-215 ◽  
Author(s):  
Ghasem Najafpour ◽  
Maedeh Sadeghpour ◽  
Zinatizadeh Lorestani

The process was effectively used for the treatment of domestic wastewater known as the activated sludge process. To predict the biomass growth, the Monod rate equation was applied in a 30 liter(s) aerated and agitated vessel. The projected data for the kinetic model were used to estimate the large scale aeration tank for the efficient oxygen transfer rate. Food to microorganism ratio (F/M) and HRT were examined for the desired rate of COD removal. More than 52% yield of organic removal was obtained. Also, the endogenous decay coefficient of 0.06 d-1 was obtained. The growth rate constant (Ks) and rate constant (k) were determined as 85.5 mg/l and 1.71 d-1, respectively. 90% COD removal was achieved with the eight-day-old sludge.


2016 ◽  
Vol 9 (2) ◽  
Author(s):  
Dinda Rita K. Hartaja ◽  
Imam Setiadi

Generally, wastewater of nata de coco industry contains suspended solids and COD were high, ranging from 90,000 mg / l. The high level of of the wastewater pollutants, resulting in nata de coco industry can not be directly disposed of its wastewater into the environment agency. Appropriate technology required in order to process the waste water so that the treated water can meet the environmental quality standards that are allowed. Designing the waste water treatment plant that is suitable and efficient for treating industrial wastewater nata de coco is the activated sludge process. Wastewater treatment using activated sludge process of conventional (standard) generally consists of initial sedimentation, aeration and final sedimentation.Keywords : Activated Sludge, Design, IPAL


2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Young H. Yoon ◽  
Jae R. Park ◽  
Sang W. Ahn ◽  
Kwang B. Ko ◽  
Kyung J. Min ◽  
...  

Hybrid Activated Sludge Process (HASP) with IMET was developed and applied to an activated sludge process for the advanced nutrient treatment in Korea. The characteristics of nitrogen removal from the HASP were investigated through a kinetic study by batch-type experiment. Online DB analysis produced from the IMET was conducted for the nutrient removal performance in the field demonstration plant treating 10,000 m3/day in G city of Korea. In this paper, we aimed to determine the effect of increasing NHM4+-N load on the specific nitrification rate (SNR) and the specific denitrification rate (SDNR) through a batch-type experiment, and to estimate the net reaction time for the phase-transfer rate using online DB analysis in the HASP operation. Experimental results include: (1) both the nitrification and denitrification followed first-order kinetics; (2) the maximum SNR and SDNR were 4.0301 mgN/gVSS·hr and 2.785 mgN/gVSS·hr, respectively; (3) comparison of reaction rates between nitrification and denitrification from the non-linear regression analysis found that nitrification rate was higher than denitrification.


1987 ◽  
Vol 22 (3) ◽  
pp. 437-443 ◽  
Author(s):  
N. Kosaric ◽  
Z. Duvnjak

Abstract Aerobic sludge from a municipal activated sludge treatment plant, sludge from a conventional municipal anaerobic digester, aerobic sludge from an activated sludge process of a petroleum refinery, and granular sludge from an upflow sludge blanket reactor (USBR) were tested in the deemulsification of a water-in-oil emulsion. All sludges except the last one, showed a good deemulsification capability and could he used for a partial deemulsification of such emulsions. The rate and degree of the deemulsifications increased with an increase in sludge concentrations. The deemulsifications were faster at 85°C and required smaller amounts of sludge than in the case of the deemulsifications at room temperature. An extended stirring (up to a certain limit) in the course of the dispersion of sludge emulsion helped the deemulsification. Too vigorous agitation had an adverse effect. The deemulsification effect of sludge became less visible with an increase in the dilution of emulsion which caused an increase in its spontaneous deemulsification.


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